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Finding the Fourth Proportional to 128.73, 177.61 and 89.94

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Solution

The fourth proportional to 128.73, 177.61 and 89.94 is: 124.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.73 : 177.61 = 89.94 : x
  2. Step 2: Convert to fraction form
    128.73/177.61 = 89.94/x
  3. Step 3: Cross multiply
    128.73x = 177.61 × 89.94
  4. Step 4: Simplify right side
    128.73x = 15,974.24
  5. Step 5: Solve for x
    x = 15,974.24/128.73
  6. Step 6: Final answer
    x = 124.09

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.